The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.
Interconnection systems for audio applications are typically simple uni-directional links that send speaker feed signals from a sound source or renderer to an array of speakers. The advent of advanced audio content, such as object-based audio has significantly increased the complexity of the rendering process and the nature of the audio content transmitted to various different arrays of speakers, that are now possible. For example, cinema sound tracks may comprise many different sound elements corresponding to images on the screen, dialog, noises, and sound effects that emanate from different places on the screen and combine with background music and ambient effects to create the overall audience experience. Accurate playback requires that sounds be reproduced in a way that corresponds as closely as possible to what is shown on screen with respect to sound source position, intensity, movement, and depth. Traditional channel-based audio systems send audio content in the form of speaker feeds to individual speakers in a listening environment. In this case, conventional uni-directional interconnects to the speakers are usually sufficient.
The introduction of digital cinema and the development of true three-dimensional (“3D”) or virtual 3D content, however, has created new standards for sound, such as the incorporation of multiple channels of audio to allow for greater creativity for content creators, and a more enveloping and realistic auditory experience for audiences. Expanding beyond traditional speaker feeds and channel-based audio as a means for distributing spatial audio is critical, and there has been considerable interest in a model-based audio description that allows the listener to select a desired playback configuration with the audio rendered specifically for their chosen configuration. The spatial presentation of sound utilizes audio objects, which are audio signals with associated parametric source descriptions of apparent source position (e.g., 3D coordinates), apparent source width, and other parameters. Further advancements include a next generation spatial audio (also referred to as “adaptive audio”) format has been developed that comprises a mix of audio objects and traditional channel-based speaker feeds along with positional metadata for the audio objects. In a spatial audio decoder, the channels are sent directly to their associated speakers (if the appropriate speakers exist) or down-mixed to an existing speaker set, and audio objects are rendered by the decoder in a flexible manner. The parametric source description associated with each object, such as a positional trajectory in 3D space, is taken as an input along with the number and position of speakers connected to the decoder. The renderer then utilizes certain algorithms, such as a panning law, to distribute the audio associated with each object across the attached set of speakers. This way, the authored spatial intent of each object is optimally presented over the specific speaker configuration that is present in the listening room.
Present interconnection systems cannot adequately take advantage of the full features and capabilities of such next generation audio systems. Such interconnects are limited to sending speaker feed audio signals, and perhaps some limited control signals, but do not have sufficient structure to exploit all of the rendering, configuration, and calibrations capabilities of the entire system. What is needed, therefore, is an interconnection system that transmits appropriate information to the renderer from the listening environment so that the renderer can transmit speaker feeds for specific speaker arrays and invoke any automated configuration and calibration routines for optimized playback of object-based audio content.